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Commit | Line | Data |
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f229f6ce PM |
1 | /* |
2 | * Rusty Russell (C)2000 -- This code is GPL. | |
3 | * Patrick McHardy (c) 2006-2012 | |
4 | */ | |
5 | ||
f6ebe77f | 6 | #include <linux/kernel.h> |
5a0e3ad6 | 7 | #include <linux/slab.h> |
f6ebe77f HW |
8 | #include <linux/init.h> |
9 | #include <linux/module.h> | |
10 | #include <linux/proc_fs.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/netfilter.h> | |
7db9a51e PNA |
13 | #include <linux/netfilter_ipv4.h> |
14 | #include <linux/netfilter_ipv6.h> | |
c737b7c4 | 15 | #include <linux/netfilter_bridge.h> |
bbd86b9f | 16 | #include <linux/seq_file.h> |
7a11b984 | 17 | #include <linux/rcupdate.h> |
f6ebe77f | 18 | #include <net/protocol.h> |
c01cd429 | 19 | #include <net/netfilter/nf_queue.h> |
7fee226a | 20 | #include <net/dst.h> |
f6ebe77f HW |
21 | |
22 | #include "nf_internals.h" | |
23 | ||
601e68e1 | 24 | /* |
0360ae41 FW |
25 | * Hook for nfnetlink_queue to register its queue handler. |
26 | * We do this so that most of the NFQUEUE code can be modular. | |
27 | * | |
28 | * Once the queue is registered it must reinject all packets it | |
29 | * receives, no matter what. | |
f6ebe77f | 30 | */ |
f6ebe77f | 31 | |
d72367b6 HW |
32 | /* return EBUSY when somebody else is registered, return EEXIST if the |
33 | * same handler is registered, return 0 in case of success. */ | |
dc3ee32e | 34 | void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh) |
601e68e1 | 35 | { |
0360ae41 | 36 | /* should never happen, we only have one queueing backend in kernel */ |
dc3ee32e EB |
37 | WARN_ON(rcu_access_pointer(net->nf.queue_handler)); |
38 | rcu_assign_pointer(net->nf.queue_handler, qh); | |
f6ebe77f HW |
39 | } |
40 | EXPORT_SYMBOL(nf_register_queue_handler); | |
41 | ||
42 | /* The caller must flush their queue before this */ | |
dc3ee32e | 43 | void nf_unregister_queue_handler(struct net *net) |
f6ebe77f | 44 | { |
dc3ee32e | 45 | RCU_INIT_POINTER(net->nf.queue_handler, NULL); |
f6ebe77f HW |
46 | } |
47 | EXPORT_SYMBOL(nf_unregister_queue_handler); | |
48 | ||
a5fedd43 | 49 | void nf_queue_entry_release_refs(struct nf_queue_entry *entry) |
daaa8be2 | 50 | { |
1d1de89b DM |
51 | struct nf_hook_state *state = &entry->state; |
52 | ||
daaa8be2 | 53 | /* Release those devices we held, or Alexey will kill me. */ |
1d1de89b DM |
54 | if (state->in) |
55 | dev_put(state->in); | |
56 | if (state->out) | |
57 | dev_put(state->out); | |
1c984f8a DM |
58 | if (state->sk) |
59 | sock_put(state->sk); | |
1109a90c | 60 | #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) |
daaa8be2 | 61 | if (entry->skb->nf_bridge) { |
c737b7c4 | 62 | struct net_device *physdev; |
daaa8be2 | 63 | |
c737b7c4 FW |
64 | physdev = nf_bridge_get_physindev(entry->skb); |
65 | if (physdev) | |
66 | dev_put(physdev); | |
67 | physdev = nf_bridge_get_physoutdev(entry->skb); | |
68 | if (physdev) | |
69 | dev_put(physdev); | |
daaa8be2 PM |
70 | } |
71 | #endif | |
daaa8be2 | 72 | } |
a5fedd43 | 73 | EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs); |
daaa8be2 | 74 | |
4bd60443 | 75 | /* Bump dev refs so they don't vanish while packet is out */ |
ed78d09d | 76 | void nf_queue_entry_get_refs(struct nf_queue_entry *entry) |
4bd60443 | 77 | { |
1d1de89b DM |
78 | struct nf_hook_state *state = &entry->state; |
79 | ||
1d1de89b DM |
80 | if (state->in) |
81 | dev_hold(state->in); | |
82 | if (state->out) | |
83 | dev_hold(state->out); | |
1c984f8a DM |
84 | if (state->sk) |
85 | sock_hold(state->sk); | |
1109a90c | 86 | #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) |
4bd60443 | 87 | if (entry->skb->nf_bridge) { |
4bd60443 FW |
88 | struct net_device *physdev; |
89 | ||
c737b7c4 | 90 | physdev = nf_bridge_get_physindev(entry->skb); |
4bd60443 FW |
91 | if (physdev) |
92 | dev_hold(physdev); | |
c737b7c4 | 93 | physdev = nf_bridge_get_physoutdev(entry->skb); |
4bd60443 FW |
94 | if (physdev) |
95 | dev_hold(physdev); | |
96 | } | |
97 | #endif | |
4bd60443 | 98 | } |
a5fedd43 | 99 | EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs); |
4bd60443 | 100 | |
26888dfd | 101 | void nf_queue_nf_hook_drop(struct net *net) |
8405a8ff EB |
102 | { |
103 | const struct nf_queue_handler *qh; | |
8405a8ff | 104 | |
8405a8ff | 105 | rcu_read_lock(); |
dc3ee32e | 106 | qh = rcu_dereference(net->nf.queue_handler); |
2385eb0c | 107 | if (qh) |
26888dfd | 108 | qh->nf_hook_drop(net); |
8405a8ff | 109 | rcu_read_unlock(); |
8405a8ff | 110 | } |
e2a75007 | 111 | EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop); |
8405a8ff | 112 | |
7db9a51e PNA |
113 | static void nf_ip_saveroute(const struct sk_buff *skb, |
114 | struct nf_queue_entry *entry) | |
115 | { | |
116 | struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); | |
117 | ||
118 | if (entry->state.hook == NF_INET_LOCAL_OUT) { | |
119 | const struct iphdr *iph = ip_hdr(skb); | |
120 | ||
121 | rt_info->tos = iph->tos; | |
122 | rt_info->daddr = iph->daddr; | |
123 | rt_info->saddr = iph->saddr; | |
124 | rt_info->mark = skb->mark; | |
125 | } | |
126 | } | |
127 | ||
128 | static void nf_ip6_saveroute(const struct sk_buff *skb, | |
129 | struct nf_queue_entry *entry) | |
130 | { | |
131 | struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); | |
132 | ||
133 | if (entry->state.hook == NF_INET_LOCAL_OUT) { | |
134 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
135 | ||
136 | rt_info->daddr = iph->daddr; | |
137 | rt_info->saddr = iph->saddr; | |
138 | rt_info->mark = skb->mark; | |
139 | } | |
140 | } | |
141 | ||
7034b566 | 142 | static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, |
960632ec AC |
143 | const struct nf_hook_entries *entries, |
144 | unsigned int index, unsigned int queuenum) | |
f6ebe77f | 145 | { |
f1585086 | 146 | int status = -ENOENT; |
daaa8be2 | 147 | struct nf_queue_entry *entry = NULL; |
e3ac5298 | 148 | const struct nf_queue_handler *qh; |
dc3ee32e | 149 | struct net *net = state->net; |
46435623 | 150 | unsigned int route_key_size; |
f6ebe77f | 151 | |
25985edc | 152 | /* QUEUE == DROP if no one is waiting, to be safe. */ |
dc3ee32e | 153 | qh = rcu_dereference(net->nf.queue_handler); |
94b27cc3 FW |
154 | if (!qh) { |
155 | status = -ESRCH; | |
81b4325e | 156 | goto err; |
94b27cc3 | 157 | } |
f6ebe77f | 158 | |
46435623 PNA |
159 | switch (state->pf) { |
160 | case AF_INET: | |
161 | route_key_size = sizeof(struct ip_rt_info); | |
162 | break; | |
163 | case AF_INET6: | |
164 | route_key_size = sizeof(struct ip6_rt_info); | |
165 | break; | |
166 | default: | |
167 | route_key_size = 0; | |
168 | break; | |
169 | } | |
bce8032e | 170 | |
46435623 | 171 | entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC); |
f1585086 FW |
172 | if (!entry) { |
173 | status = -ENOMEM; | |
81b4325e | 174 | goto err; |
f1585086 | 175 | } |
f6ebe77f | 176 | |
02f014d8 PM |
177 | *entry = (struct nf_queue_entry) { |
178 | .skb = skb, | |
1d1de89b | 179 | .state = *state, |
960632ec | 180 | .hook_index = index, |
46435623 | 181 | .size = sizeof(*entry) + route_key_size, |
02f014d8 | 182 | }; |
f6ebe77f | 183 | |
ed78d09d | 184 | nf_queue_entry_get_refs(entry); |
7fee226a | 185 | skb_dst_force(skb); |
7db9a51e PNA |
186 | |
187 | switch (entry->state.pf) { | |
188 | case AF_INET: | |
189 | nf_ip_saveroute(skb, entry); | |
190 | break; | |
191 | case AF_INET6: | |
192 | nf_ip6_saveroute(skb, entry); | |
193 | break; | |
194 | } | |
195 | ||
02f014d8 | 196 | status = qh->outfn(entry, queuenum); |
f6ebe77f | 197 | |
f6ebe77f | 198 | if (status < 0) { |
daaa8be2 PM |
199 | nf_queue_entry_release_refs(entry); |
200 | goto err; | |
f6ebe77f HW |
201 | } |
202 | ||
f1585086 | 203 | return 0; |
daaa8be2 | 204 | |
daaa8be2 | 205 | err: |
daaa8be2 | 206 | kfree(entry); |
f1585086 | 207 | return status; |
f6ebe77f HW |
208 | } |
209 | ||
7034b566 PNA |
210 | /* Packets leaving via this function must come back through nf_reinject(). */ |
211 | int nf_queue(struct sk_buff *skb, struct nf_hook_state *state, | |
960632ec AC |
212 | const struct nf_hook_entries *entries, unsigned int index, |
213 | unsigned int verdict) | |
7034b566 | 214 | { |
7034b566 PNA |
215 | int ret; |
216 | ||
960632ec | 217 | ret = __nf_queue(skb, state, entries, index, verdict >> NF_VERDICT_QBITS); |
7034b566 PNA |
218 | if (ret < 0) { |
219 | if (ret == -ESRCH && | |
960632ec | 220 | (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) |
7034b566 | 221 | return 1; |
7034b566 PNA |
222 | kfree_skb(skb); |
223 | } | |
224 | ||
225 | return 0; | |
226 | } | |
227 | ||
26dfab72 PNA |
228 | static unsigned int nf_iterate(struct sk_buff *skb, |
229 | struct nf_hook_state *state, | |
960632ec AC |
230 | const struct nf_hook_entries *hooks, |
231 | unsigned int *index) | |
26dfab72 | 232 | { |
960632ec AC |
233 | const struct nf_hook_entry *hook; |
234 | unsigned int verdict, i = *index; | |
26dfab72 | 235 | |
960632ec AC |
236 | while (i < hooks->num_hook_entries) { |
237 | hook = &hooks->hooks[i]; | |
26dfab72 | 238 | repeat: |
960632ec | 239 | verdict = nf_hook_entry_hookfn(hook, skb, state); |
26dfab72 PNA |
240 | if (verdict != NF_ACCEPT) { |
241 | if (verdict != NF_REPEAT) | |
242 | return verdict; | |
243 | goto repeat; | |
244 | } | |
960632ec AC |
245 | i++; |
246 | } | |
26dfab72 | 247 | |
960632ec | 248 | *index = i; |
26dfab72 PNA |
249 | return NF_ACCEPT; |
250 | } | |
251 | ||
b0f38338 FW |
252 | static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum) |
253 | { | |
254 | switch (pf) { | |
2a95183a | 255 | #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE |
b0f38338 FW |
256 | case NFPROTO_BRIDGE: |
257 | return rcu_dereference(net->nf.hooks_bridge[hooknum]); | |
2a95183a | 258 | #endif |
b0f38338 FW |
259 | case NFPROTO_IPV4: |
260 | return rcu_dereference(net->nf.hooks_ipv4[hooknum]); | |
261 | case NFPROTO_IPV6: | |
262 | return rcu_dereference(net->nf.hooks_ipv6[hooknum]); | |
263 | default: | |
264 | WARN_ON_ONCE(1); | |
265 | return NULL; | |
266 | } | |
267 | ||
268 | return NULL; | |
269 | } | |
270 | ||
960632ec | 271 | /* Caller must hold rcu read-side lock */ |
02f014d8 | 272 | void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict) |
f6ebe77f | 273 | { |
960632ec AC |
274 | const struct nf_hook_entry *hook_entry; |
275 | const struct nf_hook_entries *hooks; | |
02f014d8 | 276 | struct sk_buff *skb = entry->skb; |
960632ec AC |
277 | const struct net *net; |
278 | unsigned int i; | |
f1585086 | 279 | int err; |
960632ec AC |
280 | u8 pf; |
281 | ||
282 | net = entry->state.net; | |
283 | pf = entry->state.pf; | |
284 | ||
b0f38338 | 285 | hooks = nf_hook_entries_head(net, pf, entry->state.hook); |
f6ebe77f | 286 | |
daaa8be2 | 287 | nf_queue_entry_release_refs(entry); |
f6ebe77f | 288 | |
960632ec | 289 | i = entry->hook_index; |
b0f38338 | 290 | if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) { |
960632ec AC |
291 | kfree_skb(skb); |
292 | kfree(entry); | |
293 | return; | |
294 | } | |
295 | ||
296 | hook_entry = &hooks->hooks[i]; | |
297 | ||
f6ebe77f | 298 | /* Continue traversal iff userspace said ok... */ |
7ceebfe4 | 299 | if (verdict == NF_REPEAT) |
0aa8c57a | 300 | verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state); |
f6ebe77f | 301 | |
7a11b984 | 302 | if (verdict == NF_ACCEPT) { |
ce388f45 | 303 | if (nf_reroute(skb, entry) < 0) |
7a11b984 PM |
304 | verdict = NF_DROP; |
305 | } | |
306 | ||
f6ebe77f | 307 | if (verdict == NF_ACCEPT) { |
7034b566 | 308 | next_hook: |
960632ec AC |
309 | ++i; |
310 | verdict = nf_iterate(skb, &entry->state, hooks, &i); | |
f6ebe77f HW |
311 | } |
312 | ||
313 | switch (verdict & NF_VERDICT_MASK) { | |
314 | case NF_ACCEPT: | |
3bc38712 | 315 | case NF_STOP: |
4b3d15ef | 316 | local_bh_disable(); |
0c4b51f0 | 317 | entry->state.okfn(entry->state.net, entry->state.sk, skb); |
4b3d15ef | 318 | local_bh_enable(); |
f6ebe77f | 319 | break; |
f6ebe77f | 320 | case NF_QUEUE: |
960632ec AC |
321 | err = nf_queue(skb, &entry->state, hooks, i, verdict); |
322 | if (err == 1) | |
323 | goto next_hook; | |
f6ebe77f | 324 | break; |
64507fdb | 325 | case NF_STOLEN: |
fad54440 | 326 | break; |
3bc38712 PM |
327 | default: |
328 | kfree_skb(skb); | |
f6ebe77f | 329 | } |
81b4325e | 330 | |
02f014d8 | 331 | kfree(entry); |
f6ebe77f HW |
332 | } |
333 | EXPORT_SYMBOL(nf_reinject); |